Tesla had sold barely 1,000 cars when the company’s chief executive, an up-and-coming entrepreneur named Elon Musk, rang the opening bell at Nasdaq in June 2010. The initial public offering valued Tesla at $1.7 billion even though the company’s only product was its two-seat Roadster, which had a starting price of $100,000 and took seven hours to charge. Some prominent Wall Street figures were deeply skeptical. “Tesla is a sell, sell, sell,” Jim Cramer, the CNBC host, told viewers.